Clinical Approach for Treating Dilated Cardiomyopathy in a Hog-nosed Skunk (Conepatus chinga)

Abstract

Background: Dilated cardiomyopathy (DCM) is a multifactorial disease characterized by systolic dysfunction of myocardium, affecting domestic animals like dogs, cats, and ferrets. It was sporadically described in non-domestic species, generally as a necropsy observation. The hog-nosed skunk (Conepatus chinga) is a small mammal, carnivore, belonging to the Mephitidae family, found in southern South America, and considered as concerned in a conservation status of the species. The goal of this issue is report the first clinical approach of dilated cardiomyopathy in a young hog-nosed skunk, elucidating the challenging aspects of the diagnostic, therapy, and clinical outcome.  Case: A newborn hog-nosed skunk (Conepatus chinga) was found in a farm of southern Brazil in poor nutritional and behavioral conditions. Thirty days of nutritional supplementation based on cow's milk, fruits and insects were necessary to recover its body weight score and activity level. However, 2 months after adoption, the skunk showed acute dyspnea and abnormal breath sound, decreased appetite, and loss of weight. Firstly, these signs were associated with a possible pulmonary infection or other respiratory disease. However, the general cardiomegaly and pulmonary edema pattern observed on the thoracic radiography, changed the clinical approach, conducting the presumptive diagnosis to congestive heart failure (pulmonary edema) caused by an unknown cardiac disease as a dilated cardiomyopathy (CDM). An adequate physical, echocardiographic, electrocardiographic, and hematological evaluation was possible only after chemical restraint by sevofluorane. Systolic heart murmur and pulmonary cracking sounds were detected on thoracic auscultation. These findings associated to the echocardiography features of four chamber dilatation, systolic (fractional shortening-FS = 9% and ejection fraction-EF= 22%) and diastolic (mitral E/A ratio = 4.93) dysfunctions, and bilateral ventriculoatrial regurgitation (mitral and tricuspid) were highly correlated with DCM. Considering the etiologies of CDM described in domestic species and the poor nutritional condition previously observed in the case, nutritional and idiopathic etiologies of DCM were considered for this case. Therapy was based on furosemide at hospital (4 mg/kg subcutaneous, single doses) and home (2 mg/kg orally, BID), enalapril maleate (0.5 mg/kg orally, every 48 h), taurine supplementation (100 mg orally, SID), and pimobendan (0.5 mg/kg orally, BID). Clinical improvement was already observed on the second day of treatment, and monitored for 5 months, when the skunk was completely revaluated. The second echocardiographic exam showed improvement in systolic (FS = 20% and EF = 43%) and diastolic functions (mitral E/A ratio = 2.05), tricuspid regurgitation was not observed, and decrease the left atrial and ventricular dimensions were seen. Due to good clinical outcome, furosemide was gradually reduced until complete withdrawal without any clinical complications or worsening. After 30 months of therapy of pimobendan, taurine, and enalapril maleate, the skunk has good quality captive life without congestive heart failure recurrence.    Discussion: The lack of information about DCM in hog-nosed skunk turns the clinical diagnosis and therapy challenging. However, the radiographic and echocardiographic features seamed to lead the same domestic animal patterns. The therapy based on decrease the cardiac overload, increase the myocardial inotropic function (pimobendan and taurine) resulted on excellent clinical and echocardiographic outcome. Although the etiologies of DCM in this species are not stablished, the diagnostic and therapeutic approaches applied resulted on excellent clinical results, and therefore may provide useful information about this cardiac condition in skunk species. Keywords: cardiovascular, disease, Mephitidae, therapy, wild animals.